The present invention relates to a semiconductor device and a method of manufacturing the semiconductor device. For example, the semiconductor device can be preferably used for a semiconductor device having a trench-gate power MOSFET.
A semiconductor device having an insulated gate field effect transistor such as a trench-gate power metal oxide semiconductor field effect transistor (MOSFET) is known as a semiconductor device performing power switching.
In this type of semiconductor device, when a parasitic diode in the insulated gate field effect transistor performs recovery operation, a serge voltage may be generated between a source electrode and a drain electrode due to a parasitic inductance in a circuit of the semiconductor device. When the insulated gate field effect transistor is switched from on to off, the serge voltage may also be generated between the source electrode and the drain electrode due to the parasitic inductance. The serge voltage may cause breakage of the insulated gate field effect transistor or another semiconductor device.
The semiconductor device has a snubber circuit to reduce such a surge voltage. The snubber circuit is configured of a snubber part including a resistance and a capacitance coupled in series. The resistance and the capacitance coupled in series are electrically coupled in parallel between the drain electrode and the source electrode of the insulated gate field effect transistor. Examples of a document that discloses the semiconductor device having the snubber part include Japanese Unexamined Patent Application Publications No. 2017-45827 and No. 2017-143188.
In the Japanese Unexamined Patent Application Publication No. 2017-45827, the snubber part is formed directly below a region where a gate electrode of the insulated gate field effect transistor is disposed. In the Japanese Unexamined Patent Application Publication No. 2017-143188, the snubber part including a resistance, a capacitance, and a snubber electrode is formed in a snubber region defined in a semiconductor substrate.